Effects of extremely low frequency electromagnetic fields on distortion product otoacoustic emissions in rabbits.
ABSTRACT Humans are continuously exposed to extremely low frequency (ELF), electromagnetic fields (EMF), transmitted from the common sources like power stations, electric transmission lines, communication and radio-television signal transmission units. The present study aimed to assess the effects of 50 Hz ELF-EMF of 5.068 and 10.182 kV/m electric fields, which refer to the lower and upper intensity limits beyond which hazardous effects can be observed, on the auditory functions of rabbits via Distortion Product Otoacoustic Emission (DPOAE) recordings.
The study was performed on 20 healthy adult female New Zealand White rabbits randomly divided into two groups and applied 50 Hz ELF-EMF with either 5.068 kV/m (Group 1) or 10.182 kV/m (Group 2) of electric field for 3h/day during 14 days. DPOAE responses recorded on the 0th day before exposure (B-EMF) and on the 6th (A-EMF-6th) and 14th (A-EMF-14th) days after exposure (AE). Mean stimulus intensity and emission amplitudes at 1.0-8.0 kHz were analyzed.
In Group 2 rabbits, on 6th and 14th days, the DPOAE amplitudes were observed as increased at 1.5-4.0 kHz (at 2.0 and 4.0 kHz significantly) than B-EMF values. At 6.0 kHz, A-EMF-14th amplitudes were significantly lower than A-EMF values.
These results suggest that ELF EMFs might affect hearing functions by frequency dependent manner. Higher ELF EMFs exposure caused increase of cochlear activity. Ototoxic effect of 10.182 kV/m ELF EMFs may begin at the basal turn of the cochlea by reducing DPOAEs at high frequencies.
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ABSTRACT: In both living and working environment, apart from the ever present Earth's atmospheric and magnetic fields, very often there is an existing very low- frequency electromagnetic field emitted by energy plants, home, radio and TV appliances, public transport vehicles and video terminals. Low-frequency electromagnetic fields (30-300 Hz) are also present in the vicinity of high-voltage transmission lines, high and middle voltage conductors, sub-stations and industry. A large number of people who work on servicing of these plants and devices are exposed to electromagnetic fields. To a certain degree even the tenants who live and even occupy the space near high-voltage transmission lines and converters for a certain period of time as well as those who use electric home appliances in their homes are exposed to the aforementioned. Taking into consideration the recent results obtained from contemporary epidemiological examinations, the impact of these low-frequency magnetic fields are to a large degree undesirable and damaging to health. As a result, a warning has been issued about the frequent occurrence of malignant diseases, psychological disorders, genetic material damage, cardiovascular, nervous, hematopoetic system, metabolism and the occurrence of miscarriages in the exposed population.Correspondingly, there is a growing need for further research of biological effects of such radiation with an aim to bring forth both unified standards as well as legal regulation that would regulate maximum allowed time of exposure by which both duration of stay in places with higher radiation and building of new industrial plants and tenements will be determined.Acta Medica Medianae. 01/2010;